Method add_url_rule

src/flask/sansio/app.py:605–661

(
        self,
        rule: str,
        endpoint: str | None = None,
        view_func: ft.RouteCallable | None = None,
        provide_automatic_options: bool | None = None,
        **options: t.Any,
    )

    @setupmethod
    def add_url_rule(
        self,
        rule: str,
        endpoint: str | None = None,
        view_func: ft.RouteCallable | None = None,
        provide_automatic_options: bool | None = None,
        **options: t.Any,
    ) -> None:
        if endpoint is None:
            endpoint = _endpoint_from_view_func(view_func)  class="cm"># type: ignore
        options[class="st">"endpoint"] = endpoint
        methods = options.pop(class="st">"methods", None)

        class="cm"># if the methods are not given and the view_func object knows its
        class="cm"># methods we can use that instead.  If neither exists, we go with
        class="cm"># a tuple of only ``GET`` as default.
        if methods is None:
            methods = getattr(view_func, class="st">"methods", None) or (class="st">"GET",)
        if isinstance(methods, str):
            raise TypeError(
                class="st">"Allowed methods must be a list of strings, for"
                &class="cm">#x27; example: @app.route(..., methods=[class="st">"POST"])'
            )
        methods = {item.upper() for item in methods}

        class="cm"># Methods that should always be added
        required_methods: set[str] = set(getattr(view_func, class="st">"required_methods", ()))

        class="cm"># starting with Flask 0.8 the view_func object can disable and
        class="cm"># force-enable the automatic options handling.
        if provide_automatic_options is None:
            provide_automatic_options = getattr(
                view_func, class="st">"provide_automatic_options", None
            )

        if provide_automatic_options is None:
            if class="st">"OPTIONS" not in methods and self.config[class="st">"PROVIDE_AUTOMATIC_OPTIONS"]:
                provide_automatic_options = True
                required_methods.add(class="st">"OPTIONS")
            else:
                provide_automatic_options = False

        class="cm"># Add the required methods now.
        methods |= required_methods

        rule_obj = self.url_rule_class(rule, methods=methods, **options)
        rule_obj.provide_automatic_options = provide_automatic_options  class="cm"># type: ignore[attr-defined]

        self.url_map.add(rule_obj)
        if view_func is not None:
            old_func = self.view_functions.get(endpoint)
            if old_func is not None and old_func != view_func:
                raise AssertionError(
                    class="st">"View function mapping is overwriting an existing"
                    fclass="st">" endpoint function: {endpoint}"
                )
            self.view_functions[endpoint] = view_func